Intensiteettikuvio

Intensiteettikuvio, or intensity pattern, refers to the spatial distribution of light intensity on a surface or detector that results from the superposition of waves passing through apertures or around obstacles. The pattern arises from diffraction and interference and depends on the light source (wavelength, coherence) and the optical geometry (aperture shape, distance to the screen or sensor).

In the far field, also known as Fraunhofer diffraction, the intensity is proportional to the square of the magnitude of the Fourier transform of the aperture function. Classical examples include the single-slit pattern, which shows a central maximum with subsequent minima and maxima described by a sinc^2 envelope; the double-slit pattern, which consists of sharp interference fringes modulated by the single-slit envelope; and the Airy disk produced by a circular aperture.

Intensity patterns are measured with detectors such as photodiodes or CCD cameras and are fundamental to the characterization of optical components, alignment of systems, imaging, spectroscopy, and metrology. They also define the point-spread function of an imaging system, describing how a point source is imaged. The concept extends beyond optics to other wave phenomena, including acoustics and electron diffraction.

Overall, the intensiteettikuvio encapsulates how an optical system distributes energy in space, shaped by wavelength, coherence, aperture geometry, and observation distance.